Prevalence of Heterophoria in Tibetan Grade-One Students: The Lhasa Childhood Eye Study

Introduction. The study aims to explore the prevalence of heterophoria and associate factors in Tibetan grade-one students. Methods. The Lhasa Childhood Eye Study (LCES) is a school-based cohort study. 1942 grade-one students from 7 elementary schools were randomly sampled by stratified cluster sampling. Ocular examinations were performed in participants, including ocular motility, distance and near visual acuity, cycloplegic autorefraction, and stereoacuity. The near (33 cm) and distance (6 m) fixation cover test was used to differentiate orthophoria, heterophoria, and heterotropia, and the magnitude of the phoria was measured by the Maddox rod and prisma. Results. Of 1856 grade-one students completing all the ocular examinations, 1852 participants finished the ocular alignment test. The mean age was 6.82 ± 0.46 years (range 6∼10 years); 981 (52.97%) were males, and 871 (47.03%) were females. The prevalence of phoria was 22.89% (n = 424). At distance fixation, the prevalence of heterophoria, exophoria, and esophoria was 4.64%, 4.21%, and 0.43% separately, while at near fixation, the prevalence was 22.73%, 22.35%, and 0.38%. No vertical phoria was detected. The mean magnitude of heterophoria at near and distance fixation was −7.63 ± 5.15 PD (exo: −7.83 ± 4.91 PD, eso: +5.67 ± 3.61 PD) and −4.84 ± 5.94 PD (exo: −6.26 ± 4.20 PD, eso: +8.13 ± 3.04 PD). The prevalence of esophoria was associated with hyperopia (OR = 6.38, 95% CI: 1.15–35.28, P = 0.03; OR = 5.42, 95% CI: 1.04–28.24, P = 0.04) and amblyopia (OR = 16.02, 95% CI: 1.81∼141.96, P = 0.01; OR = 11.37, 95% CI: 1.34∼96.52, P = 0.03) at near and distance fixation. The prevalence of exophoria was associated with myopia at near fixation (OR = 2.43, 95% CI: 1.47–4.00, P <0.01). In the near heterophoria group, the proportion of children with abnormal stereoacuity was 23.26% (n = 97), significantly higher (χ2 = 5.70, P = 0.017) than that in orthophoria (17.99%, n = 244). Conclusions. In Lhasa, grade-one pupils have a lower prevalence of heterophoria. Near exophoria was associated with myopia, while esophoria was related to hyperopia and amblyopia both near and distance. Heterophoria may be one of the affected factors for reducing stereoacuity.

Clinical Characteristics of Patients Presenting with Headache at Binocular Vision Clinic: A Hospital Based Study

Purpose: To assess the clinical characteristics of patients presenting with headache at binocular vision clinic.Place and Duration of Study: Al-Neelain eye hospital, Sudan, from February to October 2018.Study Design: Cross-sectional study.Material and Methods: One hundred fifty patients with history of headache were included in study. Dissociated heterophoria was measured using Maddox Wing and Maddox Rod. Associated heterophoria was assessed by the Mallett unit fixation disparity and fusional vergence was measured using a prism bar. The relationship between measures was determined using the chi-squared analysis. For all statistical determinations, significance levels were set at p < 0.05.Results: Mean age was 25 ± 3.5 years. Femalesconstituted 78% and headache was significantly associated with females (P < 0.0001). Majority of patients (82%)presented with exophoria (mean = 4.74 ± 0.75 Δ Base-In) at near fixation, 10.7% were orthophoric and7.34percentage were esophoric (mean = 3.24 ± 0.5 Δ Base-Out). The association between near heterophoria andheadache was statically significant (χ2 = 7.426; p = 0.001). Association between distance heterophoria andheadache was not statistically significant (χ2 = 22.172; p = 0.265). The association between headache andpositive fusional vergence at near fixation was statically significant (p = 0.03). Leading cause of headache wasconvergence weakness exophoria (39.3%; p = 0.001), followed by convergence insufficiency (24%; p = 0.02).Conclusion: Headache was more common in females and was associated with exophoria, convergenceinsufficiency and inadequate positive fusional vergence at near fixation

Validity of Techniques to Evaluate Near Phoria

Background: While a number of previous studies have investigated the repeatability of techniques designed to measure heterophoria, there have been few studies of their validity. Accordingly, the present study examined the ability of 3 standard techniques; Von Graefe (VG), Maddox Rod (MR) and Modified Thorington (MT) tests to quantify a known change in heterophoria. Methods:The study was performed on 30 young subjects using each of the 3 procedures listed above. Near (40 cm) heterophoria was quantified both without and with an additional base-out prism. Five possible values were available, namely 2, 4, 6, 8 and 9Δ. After a period of 24 hours, the heterophoria measurement was repeated using the same technique with one of these prisms added to the refractive correction. Results:The mean heterophoria value measured before the introduction of prism using the VG procedure was significantly more exophoric than the findings obtained using the other 2 techniques (p = 0.035). No significant difference was observed between the measured and predicted change in heterophoria following the introduction of the prism for the VG and MT procedures, but a significant difference was found with the MR technique (p0.001). Conclusions:The ability to measure a known change in oculomotor deviation was significantly poorer with the MR technique, when compared with the VG and MT procedures. Given that the mean pre-prism measurement was significantly more exophoric when using the VG procedure, we recommend that MT be adopted as the technique of choice for the subjective measurement of oculomotor deviations in the clinical setting

Ambliopia anisometropia

Anisometropic amblyopia is blurred vision due to refractive anomaly without any anatomical disorders of the eyes. It is frequently found among children in their growth and development periods. The prognosis depends on the ambylopia severity, management, patient’s obedience to the management, and age. We report a case of anisometropic amblyopia in a 8-year-old boy with his main complaint was blurred vision of both eyes. The ophthalmological examination showed the visual acuity of both eyes 6/40, PH 6/9. Several tests that showed normal results were as follows: eyeball movements to all directions; pupil responses to light; Hischberg test; cover test dan cover uncover test at near and far distance fixation; alternate cover test; and worth four dots and Maddox rod tests. Cyclopegical refraction with streak retinoscopy at 50 cm distance resulted in right eye S-4.00 C-3.00 x1800 6/9 and left eye S-1.25 C-3.25 x1800 6/7.5; autorefraction of right eye S-4.50 C-3.25 x70 and of left eye S-1.25 C-4.25 x1710. Anterior and posterior segments of both eyes were normal. Conclusion: In this case, the diagnosis was confirmed as anisometropic amblyopia and compound myopic astigmatism of the right and left eyes. The prognosis was dubia ad bonam. The patient was treated with maximal correction glasses and observed for the first four weeks, and then would be evaluated continuously untill the vision was normal. Keywords: amblyopia anisometropia, vision, refraction anomalyAbstrak: Ambliopia anisometropia merupakan gangguan penglihatan akibat kelainan refraksi tanpa disertai adanya kelainan anatomik pada mata yang sering terjadi pada masa perkembangan anak. Prognosis sangat tergantung pada derajat ambliopia, penanganan, kepatuhan pasien terhadap penanganan, dan usia pasien. Kami melaporkan kasus ambliopia anisometropia pada seorang anak berusia 8 tahun, dengan keluhan utama penglihatan kedua mata kabur. Dari pemeriksaan oftalmologik didapatkan visus ODS 6/40, PH 6/9. Beberapa pemeriksaan yang dilakukan memperlihatkan hasil normal, yaitu: pergerakan bola mata ke segala arah; respon pupil terhadap cahaya; Hischberg test; cover test dan cover uncover test pada fiksasi jarak dekat dan jauh; alternate cover test; serta worth four dots test dan Maddox rod test. Pemeriksaan refraksi sikloplegik dengan streak retinoscopy pada jarak 50 cm didapatkan mata kanan S-4,00 C-3,00 x1800 6/9 dan mata kiri S-1,25 C-3,25 x1800 6/7,5 dan pemeriksaan autorefraksi mata kanan S-4,50 C-3,25 x70 dan mata kiri S-1,25 C-4,25 x1710. Pemeriksaan segmen anterior dan posterior mata kanan dan kiri dalam batas normal. Simpulan: Diagnosis pada kasus ini ialah ambliopia anisometropia ODS dan astigmatisma miopikus kompositus ODS, dengan prognosis dubia ad bonam. Terapi yang diberikan ialah kacamata koreksi maksimal dan diobservasi selama 4 minggu pertama, dan akan dievaluasi terus sampai ketajaman penglihatan normaL. Kata kunci: ambliopia anisometropia, ketajaman penglihatan, kelainan refraksi

Diagnosis of Peripheral Ocular Motor Palsies and Strabismus

This chapter reviews the physiologic basis for diplopia, including Sherington’s law of reciprocal innervation and Hering’s law of motor correspondence. Clinical testing is reviewed, including cover tests, red glass, Maddox rod, the Bielschowsky head-tilt test, and abnormal head postures. Clinical features (with illustrative video cases), etiology, and management of abducens nerve palsy, trochlear nerve palsy, oculomotor nerve palsy, and combined neuropathies are discussed, as well as Miller Fisher syndrome, amyotrophic lateral sclerosis, neuromyotonia, Brown’s syndrome and superior oblique myokymia. Disorders of the neuromuscular junction are examined, including systemic botulism, Lambert-Eaton myasthenic syndrome, and myasthenia gravis. Disorders affecting the extraocular muscles are reviewed, including chronic progressive external ophthalmoplegia, Duchenne dystrophy, myotonic dystrophy, oculopharyngeal dystrophy, congenital myopathies, Kearns-Sayre syndrome and mitochondrial myopathies. The chapter also discusses thyroid eye disease, acquired restrictive ophthalmopathies, and congenital cranial dysinnervation disorders (CCDD), Duane syndrome, horizontal gaze palsy with scloliosis, and congenital fibrosis of the extraocular muscles.